Comments

From: Colin Ian King <colin.king@canonical.com>
BugLink: https://bugs.launchpad.net/bugs/557239
The range of signal strength reported by rt2x00 is very narrow and
the base offset is too low. The original algorithm was based on a
mix of 20% from the RSSI, 40% from RX quality and 40% from TX
quality metrics.
For the rt73usb driver, the TX failure metric is a piece of fiction
and always returns success (unless there is a USB URB failure) so
this skews the TX quality metrics and hence skews the signal
strength result.
The original calculation is only really useful for a network
that you're already connected to. The reliance on RX and TX
quality metrics when not connected to a network skews the final
signal strength since the only valid metric (RSSI) is a minor
contributor to the final calculation.
A survey of most wifi drivers show that using just the RSSI is
a common method of producing a signal strength metric, so this
fix adjusts the wifi strength to be calculated just on RSSI.
This fix also adjusts the range of the DEFAULT_RSSI_OFFSET to
correctly reflect the absolute maximum range of the RSSI. The
original code was a little overzealous in providing enough
headroom.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
.../drivers/net/wireless/rt2x00/rt2x00.h | 6 +++---
.../drivers/net/wireless/rt2x00/rt73usb.h | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)